CVE-2026-115892 Wasmtime: Panic lowering a host-created component model stream into a guest that expects a different payload type
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-115892?
CVE-2026-115892 is a medium-severity vulnerability in bytecodealliance wasmtime, published on 23 Oct 2026.
Official description
Wasmtime is a runtime for WebAssembly. From 46.0.0 until 48.0.7 and 49.0.4, lowering a host-created component-model stream or future into a guest can omit a required payload-type check after the value passes through guest code and returns through StreamAny, FutureAny, Val::Stream, Val::Future, or an equivalent typed reader. A malicious guest that controls exported function types or returned values can cause the host to pass the type-erased value to a guest expecting a different payload type, which panics the Wasmtime host. This issue is fixed in versions 48.0.7 and 49.0.4.
Which versions are affected by CVE-2026-115892?
5 open source packages ship an affected version, including wasmtime.
| Package | Affected | Fixed in |
|---|---|---|
wasmtime crates.io | From 46.0.0 | 48.0.7, 49.0.4 |
wasmtime crates.io | From 46.0.0 | 48.0.7 |
wasmtime crates.io | From 46.0.0 | 48.0.7 |
wasmtime crates.io | From 49.0.0 | 49.0.4 |
wasmtime crates.io | From 49.0.0 | 49.0.4 |
How do I fix CVE-2026-115892?
Upgrade wasmtime to a fixed version for your release line: 48.0.7 or 49.0.4.
Is CVE-2026-115892 being exploited?
There is no known exploitation of CVE-2026-115892 in the wild and no public exploit code.
Sources
Also known as GHSA-9pvw-hwfg-92h5, RUSTSEC-2026-0378, UBUNTU-CVE-2026-115892.